Osteology

Question 1

How are bones o the skull divided?

Answer 1

Neurocranium

Viscerocranium

Question 2

What is the neurocranium?

Answer 2

Calvaria - skul cap
Cranial floor
Cranial cavity

Question 3

What is the role of the neurocranium?

Answer 3

Encase and protect the brain

Question 4

How many bones make up the neurocranium?

Answer 4

8

Question 5

How many bones make up the viscerocranium?

Answer 5

14

Question 6

What is the viscerocranium?

Answer 6

The bones that make up the face and jaw

Question 7

What bones make up the calvaria?

Answer 7

Frontal
Parietal
Occipital
Sphenoid

Question 8

What are the sutures?

Answer 8

Tough fibrous joints between bones - where soft as an infant

Question 9

What are the different sutures?

Answer 9

Coronal suture - between parietal bones and frontal bone

Sagittal suture - between parietal bones

Lambdoid suture - between parietal bones and occipital bone

Question 10

What is the point between the coronal and sagittal sutures called?

Answer 10

Bregma

Question 11

What is the point between the sagittal and lambdoid suture called?

Answer 11

Lambda

Question 12

What are fontanelles?

Answer 12

Areas of membrane between bones in infants that allow the growth of the infant brain

Question 13

When do the fontanelles fuse?

Answer 13

Anterior = 18 months - 2 years

Posterior = 1-3 months

Question 14

What is the structure of the bone in the calvaria?

Answer 14

Trilaminar bone

• outer table = compact bone
• diploe = spongy bone
• inner table - compact bone

Question 15

What is periosteum?

Answer 15

Covering of the surface of the outer and inner table of bones that is continuous through sutures

Question 16

Where does the middle meningeal artery lie?

Answer 16

Between periosteum and inner table of bone

Question 17

What is the clinical relevance of the periosteum?

Answer 17

Bleeds from middle meningeal artery strip away periosteum but are contained by sutures - gives the shape of extradural haemorrhages

Question 18

What bones form the cranial floor?

Answer 18

Frontal 
Ethmoid 
Sphenoid
Temporal 
Occipital

Question 19

What are the areas of the cranial floor?

Answer 19

Anterior fossa
Middle fossa
Posterior fossa

Question 20

What are the borders of the anterior fossa?

Answer 20

Anterior/lateral = frontal bone

Posterior/medial = limbus of sphenoid

Posterior/lateral = lesser wing of sphenoid

Floor = frontal + ethmoid + sphenoid

Question 21

What is found in the anterior fossa?

Answer 21

Crista galli - attachment for falx cerebri

Cribiform plate - supports olfactory bulb

Question 22

What are the borders of the middle fossa?

Answer 22

Anterior/lateral = lesser wing of sphenoid

Anterior/medial = limbus of sphenoid

Posterior/lateral = petrous part of temporal bone

Posterior/medial = dorsum sellae

Question 23

What is found in the middle fossa?

Answer 23

Optic canal 
Superior orbital fissure 
Foramen rotundum 
Foramen ovale 
Foramen spinosum 
Foramen lacerum 
Carotid canal

Question 24

What passes through the optic canal?

Answer 24

CNII - optic

Ophthalmic artery

Question 25

What passes through the superior orbital fissure?

Answer 25

``` CNIII - oculomotor CN IV - trochlear CNVa - trigeminal CNVI - abducens Ophthalmic veins ```

Question 26

What passes through foramen rotundum?

Answer 26

CNVb - trigeminal

Question 27

Where does the foramen rotundum open into?

Answer 27

Pterygopalatine fossa

Question 28

What passes through the foramen ovale?

Answer 28

CNVc - trigeminal

Question 29

Where does the foramen ovale open into?

Answer 29

Infratemporal fossa

Question 30

What passes through the foramen spinosum?

Answer 30

Middle meningeal artery | Middle meningeal vei

Question 31

Where does the foramen spinosum open into?

Answer 31

Infratemporal fossa

Question 32

What passes through foramen lacerum?

Answer 32

Filled with cartilage

Question 33

What passes through the carotid canal?

Answer 33

Internal carotid

Question 34

What are the borders of the posterior fossa?

Answer 34

Anterior/medial = dorsum sella Anterior/lateral = petrous bone Posterior = occipital bone Floor = temporal + occipital

Question 35

What is found in the posterior fossa?

Answer 35

Internal acoustic meatus Hypoglossal canal Jugular foramen Foramen magnum

Question 36

What passes through the internal acoustic meatus?

Answer 36

CNVII - facial | CNVIII - vestibulocohlear

Question 37

What passes through the hypoglossal canal?

Answer 37

CNXII - hypoglossal

Question 38

What passes though the jugular foramen?

Answer 38

CNIX - glossopharyngeal CNX - vagus Internal jugular vein

Question 39

What passes through the foramen magnum?

Answer 39

Medulla of brainstem Meninges Vertebral arteries Spinal accessory nerve

Question 40

What is the pterion?

Answer 40

Thinnest area of skull

Question 41

What is the clinical relevance of the pterion?

Answer 41

Easy to fracture Underlying anterior branch of the middle meningeal artery can cause an extradural haemorrhage

Question 42

What are the signs of skull base fractures?

Answer 42

Raccoon eyes Battle sign - bruising behind ears Haemotypanum CSF ottorhea/rhinorrhea

Question 43

What bones make up the viscerocranium?

Answer 43

``` Nasal Zygomatic Lacrimal Maxilla Mandible ```